Refrigeration



Jan. 1931- E. B. MILLER ET AL 1,790,067

REFRIGERATION Original Filed July 22, 1924 2 Sheets-Sheet '1 Jan. 27, 1931. E. B. MILLER ETAL REFRIGERATION Original Filed July 22, 1 2 Sheets-Sheet 2 Patented Jan. 27, 19.21

UNITED STATES PATENT OFFI 'ERNEST' B. MILLER. AND BENZON, OF BALTIMORE, 'MARYLAND, ASSIGNORS TO THE SILICA GEL CORPORATION, OF BALTIMORE MABYLAND, A CORPORATION OF MARYLAND REFRIGERATION Application filed July 22, 1924, Serial No. 727,447. Renewed December 29, 1927.

This invention relates to refrige tion and more particularly to a species of he invention disclosed in application 675,929. This prior application discloses a -method of refrigeration consisting in adsorbing in a porous material, ,vapor from a liquid, the adsorption taking place substantially in the absence of ermanent gases, the evaporation of the iquid causing the refrigerating effect. The porous material adsorbs the vapor in its pores and thereafter the material is treated to liberatethe adsorbed vapor, so that the material may be used for another adsorbing cycle.

One of the principal features of the present invention resides in the fact that the adsorbent is circulated, being used over and rom the refrigover and likewise the vapor crating liquid is circulated so that it also is used over and over.

An apparatus for carrying out the method of the present invention comprises an evaporator, an adsorber, and an activator, said adsorber being in communication with the evaporator, both said parts being substantially free from permanent gases. Means is provided to feed the adsorbing material into the vapor in the adsorber, whereby said vapor is adsorbed causing evaporation of the liquid and thus feet. The adsorbing material is then discharged into the activator where the vapor is driven 0E and thereafter the adsorbing material is again fed into the adsorber. The vapor driven off from the material in the activator is condensed and returned to theliquid in the evaporator.

In order to maintain the evaporator and adsorber free from permanent gases, a small vacuum pump has its inlet in c0mmunication therewith. A 7

Other objects and features of novelty will be apparent from the description taken in connection with the drawings, in which:

Figure 1 is a longitudinal vertical sectional view through an apparatus constructed in accordance with the present invention;

Figure 2 is an end elevation of the appa-' ratus, certain parts being shown in section;

and

giving a refrigerating ef-- which is evaporated to obtain the refrigerat-,

ing effect. In order to free the adsorber and evaporator of permanent gases and maintain them substantially free of such gases, means,

such as a motor driven vacuum pump 214, is

providedfsaid pump havin its inlet in com- 7 with the adso'r or by means of munication pipe 214. v

The adsorbing material, in finely divided condition, is fed into the adsorber 213, passes therethrough and is discharged into the activator 239, and then by means of conveyor 241'is returned to the adsorber. The activator 239 is in communication with a condenser'234 wherein the vapor liberated from the adsorbing material is condensed and returned to the evaporator by means of pipe It will be noted that the adsorbing material circulates in a closed cycle, first adsorbing vapor, then being treated to liberate the adsorbed vapor and thereafter being returned to the adsorber for use again. Y Likewise, the refrigerating liqui'd circulates in a closed cy e. It is adsorbed in the porous material, th reafter freed therefrom, then condensed in a condenser 234, and finally returned to the evaporator 210.

The adsorber of the apparatus consists of a cylindrical casing 244 having one end A closed by a head 245 and the other byla partition, consisting of a plate 246 and eat insulating disk 246*. The adsorbing material supplied to the adsorber through the passage 238 formed in the nozzle 247 is agitated within the adsorber by any suitable means. As shown, a shaft 248 mounted in bearings 249 and 250 within the adsorber, carries 'a plurality of spiders 251, to the ends of the arms of which is secured a hollow rim 252 substantially rectangular in cross section.

One end of shaft 248 projects through a transverse screen 253, which is spaced from the head 245, thus forming a chamber within which is disposed a worm wheel 254 secured a to said shaft 248. A motor frame forms a llO .casing 255, secured to the adsorber housing 244 and in communication with the interior of said adsorber, a heat insulating washer 255 being interposed between the caslng and housing. The motor shaft 255,, projects into the chamber 256 and carries a worm 257 gearing with the worm wheel 254. In this manner the shaft 248 is rotated by means of the motor and yet no stufiing boxes where leakage can occur, are employed, since the motor frame is in direct communication with the adsorber then is discharged or spilled out through said discharge opening 252 when the buckets are traveling through the upper half of the rotation, so that the adsorbing material falls through the adsorbing chamber. As there are a number of these devices along the length of the chamber, thetadsorbing material is very thoroughly agitated and distributedthroughout the entire volume of said .chamber. and advanced toward the left as viewed in Figure 1-. Any other suitable means for this purpose may be employed. As shown the spiders 251 are held in spaced relation by sleeves 252 interposed between adjacent spiders. To cause the spiders to rotate with shaft 248', said shaft has flanges 252 secured thereto and'rods 252 pass throu h saidflanges and spiders and clamp the w oleassembly together.

The partition 246 is provided with a central opening aligned with the shaft 248, and a worm housing -258 extends throu h this opening. On the adsorber side this ousing has a hopper 259 into which the last series of buckets .252 discharge the adsorbing material. The shaft 248 is extended through this worm housing 258 and carries a worm 259 by means of which the adsorbing material is conveyed horizontally to a discharge hopper 260.

Itwill be noted that the helix forming the T worm to the left of'a point directly .under the center of said disc arge hopper 260 is K reversed with respect to the helix at theright of said point. This novel construction is provided so that the adsorbing material willbe positively forced upwardly through the discharge hopper 260, a sufiicient column of the adsorbing material being maintained .within the discharge hopper, so that any difierence of pressure between the interior of the worm housingand the activator chamber will not destroy the seal effected by said column of ad- .spider 263, supported in bearings 264 and 265. As shown, at its left end, this spider has a sprocket 266 driven by a chain 267 from a sprocket 268 on worm shaft 269. The adsorbing material falls throu hthe passage 240 to the worm 241 within ousing 270.

This worm conveys the material to the supply passage 238, and the material is cooled in its passage by water in jacket 27 0. At its right and end, the worm has its helix reversed with respect to the helix on the main portion of the worm for the same purpose as described in connection with forcing the material up wardly through the discharge hopper 260.

The worm shaft 269 at its right hand end has a sprocket wheel 271 driven by a chain 272.

from a sprocket 273 on shaft 248. Thus all ,the moving parts of the apparatus, with the exception of the vacuum pump, are driven from the motor 255.

The condenser 234 may be supplied with cooling water through the inlet 274 and d1scharge the same through an outlet 27 5.

The pressure in the condenser is s11 htly greater than in the evaporator 210 an this difference in pressure causes the condensed liquid to be returned to the evaporator through conduit 243.

The pores of the adsorbing material required in the present method are ultra-microscopic, so that it is a very difiicult matter to accurately determine and define their slze, ,One satisfactory method of comparing the size of the pores in two bodies and also the" total volume of these pores consists in deterfnining the amount of water-that one gram of each ,body'will adsorb when exposed to water vapor under definite conditions oftemperature and partial pressure. The amount of water vapor adsorbed by a porous body at a given temperature and partial. pressure depends both upon the size of the pores and n on the total interior volume of. said pores. TYIUS, two materials may have pores such that the internal volume of'the pores in a gramo one material is the same as'in a gram of the other, and yet the pores in one may be smaller than in the other. The one'having the smaller pores will adsorb vapor at lower partial pressures than the other; In other words, very small pores are required in order to adsor vapors at low partial pressure. To-illustrate, assume that a building brick has the same internal volume as an equal Weight of silica gel. The brick, however, will adsorb substantially no water vapor at pressures below the normal vapor pressure of water, whereas the silica gel will adsorb large amounts at pressures-very much lower than the normal vapor pressure of water. This is explained as follows: A liquid that wets a capillary tube will rise in the tube above the level of the surface of the liquid surrounding the same, the extent of the rise varying with the diameter of the tube. The vapor pressure of the liquid inside the tube is smaller than the vapor pressure at the level surface of the liquid outside the tube. This lowering of the vapor pressure by the liquid within the capillary tube is not appreciable until the diameter of the tube is extremely small, and the smaller the bore of the tube, the greater the decrease in, vapor pressure. Consequently the vapor pressure within the pores of a body having small pores is less than in a body having large pores, with the result that the body having the smaller pores will adsorb vapors and gases at low partial pressures.

Thus, by determining the amount of a given vapor, water for example, which may be adsorbed by each of two porous bodies under the same condition of temperature and partial pressure, we have a means of comparing the size and volume of the pores in the two adsorbents. For example, a sufiicient percentage of the total internal volume in silica gel is made up of such small pores that the gel will adsorb water vapor to such an extent that it will contain, at 30 C. about 21% of its weight of water when in equilibrium with water vapor at a partial pressure of substantially 22 mm. of mercury. Keiselguhr and boneblack under the above conditions will adsorb practically no water because the pores are too large. On the other hand highly activated charcoal, such as cocoanut charcoal activated in the presence of steam will adsorb more water than the silica gel mentioned above. It follows, therefore, that keiselguhr and boneblack have practically no pores as small as the greater part of the pores in silica gel. On the other hand, highly activated charcoal has more small pores than silica gel.

Materials suitable for the present invention should have pores of such size that the material will adsorb water vapor to such an extent as to contain not less than 10% of its own weight of water when in equilibrium with water vapor at 30C. and a partial pressure of substantially 22 mm. of mercury.

Preferably silica gel is porous material. As stated this material has pores of such size that it will adsorb water vapor to such an extent as to contain substantially 21% of its own weight of water when in equilibrium with water vapor at 30 C. and a partial pressure of substantially 22 mm. of mercury. But other adsorbents employed as the might be used provided they have a sixthcient percentage of their internal volumes made up of small pores. Thus cocoanut charcoal activated in the presence of steam might be used with such' liquids as can be easily liberated from the charcoal after being adsorbed therein. used, also, provided they aremade with pores of the size required for this invention, i. e.., gels of oxide of tin, aluminum, tungsten, titanium, iron, combinations of two or more of these oxides, or other metallic oxides, and gels consisting of silica oxide with one or more of the foregoing oxides.

The adsorbing action is a purely physical phenomenon, and involves no chemical action. Any body or material having pores of the size and quantity defined herein will act as stated and is suitable for use as an adsorbent in the present apparatus. At thepresent time, however, we have found silica Other-gels might be v gel to be the most satisfactory adsorbent for vapor from the liquid in the evaporator. In stating that the adsorbents for the present invention should adsorb not less than 10% of their, Weight of water vapor, we do not mean that is an exactline of demarcation between satisfactory and unsatisfactory adsorbents. The limit of 10% is intended to indicate in general about the maximum size pores that can be employed'with some degree of success. Of course, for best results matlerials having smaller pores should be use Although one embodiment of the invention has been described in detail, it is'to be understood that the invention is not thus limited, but includes modifications and changes which come within the scope of the appended claims.

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is:

1. A method of refrigeration, consisting in evaporating a liquid, adsorbing the vapor in a porous adsorbent material substantially in the absence of permanent gases, removing the material from the vapor, liberating the adsorbedv vapor 'from the material and again bringingthe material into contact with the vapor, the material having pores of such size that itwill adsorb water vapor to such an extent as to contain not less than about 10% of itsown weight ofwater when in equilibrium with water vapor at 30 C. and a partial pressure of substantially 22 mm. of mercury. I

2. A method of refrigeration, consisting in evaporating a liquid, adsorbing'the vapor in'a porous adsorbent material substantially rial into contact withthe vapor, the ma-- terial having pores of such size that it will, adsorb water vapor to such an extent as to contain not less than about 10% of its own weight .of water when in equilibrium with water vapor at C. and a partial pressure of substantially 22 mm. of mercury. r

3. A method of refrigeration, consisting in evaporating a liquid, adsorbing the vapor in a porous adsorbent material substantially in the absence of permanent gases, removing the material from the vapor, liberating the adsorbed vapor from the material, condensing the vapor thus liberated and returning it to said liquid, and again bringin the material into contact withe the vapor, t e material having pores of such size thatit will adsorb water vapor to such an extent as to contain not less than about 10% of its own weight of water when in equilibrium with water vapor at 30 C. and a partial pressure of substantially 22 mm. of mercury;

4. A method of refrigeration, consisting in evaporating a liquid, adsorbing the vapor in a porous adsorbent material substantially in the absence of permanent gases, removing the material from the vapor, liberating the adsorbed vapor from the material, condensing the vapor thus liberated and returning it to said liquid, cooling said material, and again bringing the material, into contact with the vapor, the material having pores of such size that it will adsorb watervapor to such an extent as to contain not less than about 10% of its own weight of water when in equilibrium with water vapor at 30 C. and

a partial pressure of substantially 22 mm.

vapor, said material being ahard porous gel having pores of such size that it will adsorb water vapor tosuch an extent as to contain about 21% of its own weight of water when in equilibrium with water vapor at substantially 30 C. and a partial pressure of sub stantially 22 mm. of mercury.

6. A method of refrigeration, consisting 1 n evaporating a liquid, adsorbing the vapor in a porous adsorbent material substantially in the absence of permanent gases, removing the material from the vapor, liberating the adsorbed vapor from the material, cooling the material, and again bringing the material into contact with the vapor, said material being a hard porous gel having pores of such size that it will adsorb water vapor to such an extent as to contain about 21% of its own weight of water when in equilibrium with water vapor at substantially 30 C. and

a partial pressure of substantially 22 mm. of mercury. g

7. A method of refrigeration, consisting in evaporatin a liquid, adsorbing the vapor in a porous a sorbent material substantially in the absence of permanent gases, removing the, material from the vapor, liberating the adsorbed vapor from the material, condensing the vapor thus liberated and returning it to said liquid, and again bringing the material into contact with the vapor, said material bein a hard porous gel having pores of such slze that it will adsorb water vapor to such an extent as to contain about 21% of .its own weight of water when in equilibrium mercury.

8. A methocPof refrigeration, consisting in evaporating a liquid, adsorbing the vapor in a porous adsorbent material substantially in the absence of permanent gases, removing the material from the vapor, liberating the adsorbed vapor from the material, condensing the vapor thus liberated and returning it to said liquid, cooling said material,and again bringing the material into contact with the vapor, said material being a hard porous gel having pores of such size that it will adsorb water vapor tosuch an extent as to contain about 21% of its own weight of .water when in equilibrium with water vapor at substantially 30 C. and a partial pressure of substantially 22mm. of mercury.

9. Apparatus of the character described, including in combination, an evaporator sub stantially free of permanent gases adapted to contain a body of liquid, an adsorber substantially free of permanent gases in communication with said evaporator, means to feed a porous adsorbing material through said adsorber but out of contact with said body of liquid, whereby the material adsorbs vapor from said liquid in its pores, an activatorinto which the material is discharged from the adsorber, means for sealing the. adsorber and activator against the passage of vapor from one to the other, and means to return the activated material to the adsorber for another cycle.

10. Apparatus of the character described, including in combination, an adsorber having a part adapted to contain a body of liquid, 7 means to maintain said adsorber substantially free of permanent gases,'means to feed. a porous adsorbent material through said adsorber but out of contact with said liquid, whereby the vapor from said liquid is adsorbed by said material, an activator into which said material is discharged from the stantially free of 11. Apparatus of the character described, including in combination, an adsorber subpermanent tgases adapted 1n one art to contam a body 0 liquid means to fee a porous adsorbent material through said adsorber but out of contact with said liquid, whereby the material adsorbs vapor from said liquid, anactivator into which, the material is dischar ed from the adsorber, means for sealing sairf adsorber and activator against passage of vapor or gas from one to the other, a condenser in communication with said activator and adsorber to condense and return to said body of liquid vapor driven off from the material in the activator, and means to return the activated material to the adsorber for another cycle.

12. Apparatus of the character described, including in combination, an adsorber substantially free of permanent gases, adapted in one part to contain a body of liquid, means to feed a porous adsorbing material throu h said adsorber but out of contact with sald liquid, whereby the material adsorbs vapor from said liquid, an activator into which the material is discharged from the adsorber, means for sealing said adsorber and activator against passage of vapor or gas from one to the other, and means to cool and return the material from the activator to the adsorber for another cycle.

13. Apparatus of the character described, including in combination, a casing having two chambers, an evaporator adapted to contain a body of li uid, the first of said chambers being an ad sorbing chamber and communicating with said evaporator, means to maintain said evaporator and adsorber substantially free of permanent gases, means to feed a porous adsorbent material through said adsorbing chamber and into the second chamber, means sealing said chambers against flow of va or from one to the other, said second cham er constitutin an activator and adapted to liberate the a sorbed vapor from the material, means to convey the activatedmaterial from the second chamber back through an opening into the first chamber, and means to prevent flow of vapor through the last mentioned opening.

14. Apparatus of the character described, including in combination,.two chambers, an evaporator in communication with the first or adsorbing chamber, a liquid in said evaporator, means to feed a porous adsorbing material through said first chamber whereby vapor from the liquid is adsorbed by said material, a discharge conduit connecting said chambers, means to effect a flow of said materialthrough said conduit, means to prevent flow of gas or vapor from one chamber to the other comprising means to maintain in said conduit a column of the material of suificient length to resist movement because of the difference of pressures in the two chambers, said second chamber having therein means to activate the material, means to return vapor liberated from the material to said evaporator, and means to return the actis vated material from the second chamber to the first chamb'er. v

15. Apparatus of the character described, including in combination, two chambers, an evaporator in communication with the first or adsorbing chamber, a liquid in said evaporator, means to feed a orous adsorbin material through the first c amber and disc arge it into the second, whereby vapor from the liquid in the evaporator is adsorbed by the material, means 1n the second chamber for activating the material, a conduit connecting the second and first chambers, means for effecting a flow; ofthe activated material in said conduit from the second to the first chamber, and means to seal said conduit against the flow of gas or vapor from one chamber to the other comprising means to maintain in the conduit a column of the material of sufficient length to resist movement because ofdifierence of pressures in the two chambers.

16.- Apparatus of the character described, including in combination, an evaporator adapted to contain liquid, an adsorber, an activator, means to feed a porous adsorbing material through said adsorber and discharge it into said activator wherein the material is liberated of the vapor adsorbed in the adsorber, means to return the material from the activator to the adsorber, and means to feed the material through the activator actuated from the meanslast above mentioned.

17. Apparatus of the character described, including in combination, an evaporator adapted to contain liquid, an adsorber adapted to contain a porous adsorbing material in communication with the evaporator, an activator adapted 'to liberate from the material vapor adsorbed in the adsorber, means within the adsorber to feed material therethrough and discharge it into the activator, a motor in said adsorber for actuating said means, and means to return the material from the activator to the adsorber actuated from the first mentioned means.

18. Apparatus of the character described, including in combination, an evaporator adapted to contain a supply of liquid, an adsorber in communication therewith, rotatable means to feed a orous material through said adsorber where y vapor from the liquid is adsorbed in the pores of the material, an activator, means to feed the material therethrough, means to return the material from the activator to the adsorber, and a motor in the adsorber for actuating all of said means.

19. Apparatus of the character described, including in combination, an evaporator adapted to contain liquid, an adsorber in communication therewith, an activator, and

means to circulate a porous adsorbent material through the adsorber and activator and back to the adsorber, whereby the material takes up vapor in its pores in the adsorber, has the vapor liberated in the activator and is then returned to the adsorber for use again.

20. Apparatus of the character described,

including in combination, an evaporator ada ted to contain liquid, anadsorber in commun'cation therewith, an activator, means to circulate a porous adsorbent material through the adsorber and activator and backto the adsorber, whereby the material takes up Vapor in its pores in the adsorber, has the vapor liberated in the activator and is then returned to the adsorber for use again, and

a vacuum pum having its inlet connected to the adsorber ormaintaining the adsorber and evaporator substantially free of permanent gases.

21. Apparatus of the character described, including in combination, an evaporator a pted to contain liquid, an adsorber in communication therewith, an activator, all of said parts being substantially free of permanent gases, means to circulate a porous adsorbent material through said adsorber and activator and back to the adsorber, whereby the material takes up vapor from the liquid in its pores in the adsorber and has the vapor liberated therefrom in the activator and is then returned to the adsorber for use 22. A method of-refrigeration consisting in evaporating a liquid, adsorbing the vapor in a porous adsorbent material in the substantial absence of permanent gases removing the material from the vapor, liberating the absorbed vapor from the material, an again bringing the material into contact with the vapor. s

23. A method of refrigeration consisting in evaporating a liquid, adsorbing the vapor in a porous adsorbent material in the substantial absence of permanent gases, removing the material from the vapor, liberatin the adsorbed vapor from the material, coo I ing the material, and again bringing the material into contact with the vapor.

24. A method of refrigeration consisting in evaporating a liquid, adsorbing the vapor in a porous adsorbent material in the substantial absence of permanent gases, removing the material from' the vapor, liberating the adsorbed vapor from the material,

stantial absence of permanent gases, removing the material from the vapor, liberating the adsorbed vapor from the material, condensing the vapor thus liberated and returnin evaporating a liquid, adsorbing the vapor in a porous adsorbent material in the substantial absence of permanent gases, lsolatlng the material from the vapor, liberating the adsorbed vaporv from the material, and again bringing said vapor and material into contact.

In testimony whereof we hereunto aflix our signatures.

ERNEST B. MILLER. AXEL BENZON.

condensing the vapor thus liberated and returning it to said liquid, and again bringing the material into contact with the vapor.

v25. A method of refrigeration consisting in evaporatinga liquid, adsorbing the vapor in a porous adsorbent material in the sub 

